Tension mask frame assembly manufacturing apparatus and method

ABSTRACT

Disclosed is a tension mask frame assembly manufacturing apparatus for mounting a tension mask on a rectangular frame having: a pair of support frame parts to which mutually facing edges of a tension mask having a rectangular sheet shape are fixed; and a pair of connection frame parts for mutually connecting both ends of the support frame parts. The manufacturing apparatus comprises: a frame loading unit for loading the tension mask frame assembly; a pressing unit for pressing the support frame parts along the direction of the plate surfaces of support frames between both ends thereof; and a control unit for controlling the pressing unit so as to pre-deform the support frames in correspondence to at least a part of the bending deformation amount of the support frame parts according to the weight of the support frame parts and the tension of the tension mask.

TECHNICAL FIELD

The present invention relates to an apparatus for manufacturing atension mask-frame assembly, which is capable of minimizing a change inpitch of a tension mask according to deformation of a frame, and amethod for manufacturing a tension mask-frame assembly.

BACKGROUND ART

Generally, among display devices, an organic light-emitting diode (OLED)has advantages such as a wide viewing angle, excellent contrast, andfast response speed.

The OLED is a display element in which holes injected in a positiveelectrode and electrons injected in a negative electrode are recombinedin an inner organic light-emitting layer to emit visible light anddisplay necessary information to humans. Unlike a liquid crystal display(LCD), a self-emission type element, i.e., the OLED, does not require aback light unit (BLU) and has a simple structure and thus is thin andvery light. In addition, the OLED may have a faster response speed and awider viewing angle as compared with the LCD and thus may implement ahigh contrast ratio and image quality at any angle. In addition, anentire panel may have a light transmittance ratio of 23% which is threetimes a light transmittance ratio of the LCD, and the OLED may beapplicable to a flexible substrate. Thus, the OLED may be ideal forimplementing a transparent display and a flexible display. Based on suchadvantages, the OLED receives huge attention as next generationtechnology which will dominate the display industry after the LCD.However, since an organic material is used as a main component of theOLED, the OLED is vulnerable to moisture and oxygen. Thus, the OLEDfundamentally has a short lifespan. In addition, currently, the OLED ismore expensive than the LCD, and it is difficult to manufacture the OLEDso as to have high resolution and a large area.

Electrodes and intermediate layers including a light-emitting layer inthe OLED may be formed through various methods, one such method is adeposition method. In order to manufacture the OLED using the depositionmethod, a fine metal mask (FMM) having the same pattern as that of athin film or the like to be formed on a substrate is aligned, and a rawmaterial of the thin film is deposited to form a thin film with adesired pattern.

When an area of the fine metal mask is increased, the number of errorsin etching for forming a pattern is increased, a sagging phenomenon of acenter portion of the fine metal mask is increased due to the own weightof the fine metal mask. Thus, recently, a mask-frame assembly in a typeof a split mask, in which a mask is formed into several stick shapes andthen is attached to a frame to use, has been preferred. Use of thissplit mask also has an advantage in that, when there is a problem insome split masks of an entire mask-frame assembly, only correspondingsplit masks may be replaced.

A deposition method includes a point source bottom-up deposition method,a point source top-down deposition method, and a linear source verticaldeposition method.

In order to mass-produce an OLED display for a mobile phone, a size ofglass for deposition is increased. As the size of the glass fordeposition is increased, a size of a frame is increased. When pointsource bottom-up or top-down deposition is performed using a framehaving a large size, since a sagging phenomenon of a mask is increasedat a center of a frame, adhesion between the glass and the mask islimited, resulting in deposition defects. Therefore, it is advantageousto apply a linear source vertical vacuum deposition method as the sizeof the glass is increased.

In the linear source vertical vacuum deposition system, a tension maskframe is deformed according to the load thereof due to gravity. Suchdeformation of the frame caused by the load causes a change in thepattern of a fixed tension mask, resulting in an error in patternformation during a deposition operation.

DISCLOSURE Technical Problem

In order to solve above problems, the present invention is directed toproviding an apparatus for manufacturing a tension mask-frame assembly,which is capable of minimizing a change of a frame caused by the load ofthe frame and tension of a tension mask during welding of the tensionmask and the frame, and a method for manufacturing a tension mask-frameassembly.

Technical Solution

In order to achieve the above objects, provided is an apparatus formanufacturing a tension mask-frame assembly in which a tension mask ismounted on a frame which has rectangular frame shape and includes a pairof support frames, to which opposite edges of the tension mask with arectangular sheet shape are fixed, and a pair of connection framesconfigured to connect both ends of the support frames to each other. Theapparatus includes: a frame loading unit configured to load a tensionmask-frame assembly; a pressing unit configured to press the supportframe between both ends thereof in a plate surface direction of thesupport frame; and a control unit configured to control the pressingunit to pre-deform the support frame in accordance with at least aportion of a bending deformation amount of the support frame, caused byown weight of the support frame and tension of the tension mask.According to the apparatus for manufacturing a tension mask-frameassembly, own weight deformation of the support frame of the tensionmask-frame assembly may be minimized during vertical vacuum depositionby pre-deforming the frame in accordance with deformation caused by theown weight of the frame, thereby reducing an error in pattern formation.

The pressing unit may include a plurality of inward pressing memberswhich are spaced apart from each other in a lengthwise direction of thepair of support frames and press the pair of support frames toward theinside of the frame. When deformation corresponding to tensiondeformation of the tension mask and deformation corresponding to ownweight deformation are generated in the same direction, the inwardpressing members may perform additional pressing. When the deformationcorresponding to the tension deformation of the tension mask and thedeformation corresponding to the own weight deformation are generated inopposite directions, the inward pressing members may perform offsetpressing.

The pressing unit may include a plurality of outward pressing memberswhich are spaced apart from each other in the lengthwise direction ofthe pair of support frames and press the pair of support frames towardthe outside of the frame. When the deformation corresponding to thetension deformation of the tension mask and the deformationcorresponding to the own weight deformation are generated in the samedirection, the inward pressing members may perform additional pressing.When the deformation corresponding to the tension deformation of thetension mask and the deformation corresponding to the own weightdeformation are generated in opposite directions, pressing may beperformed using the outward pressing members.

The control unit may control the pressing member based on a predictedown weight deformation amount of each of the pair of the support framesand a tension deformation amount of the tension mask.

According to an embodiment of the present invention, provided is amethod of manufacturing a tension mask-frame assembly in which a tensionmask is mounted on a frame which has rectangular frame shape andincludes a pair of support frames, to which opposite edges of thetension mask with a rectangular sheet shape are fixed, and a pair ofconnection frames configured to connect both ends of the support framesto each other. The method includes: loading the frame on a frame loadingunit; pre-deforming the support frame in accordance with at least aportion of a bending deformation amount of the support frame, caused byown weight of the support frame and tension of the tension mask;clamping the tension mask on the pre-deformed frame; tensioning thetension mask; and fixing the tensioned tension mask to the pre-deformedframe

Advantageous Effects

According to an apparatus and method for manufacturing a tensionmask-frame assembly, own weight deformation of a support frame of atension mask-frame assembly can be minimized during vertical vacuumdeposition by pre-deforming the frame in accordance with deformationcaused by the own weight of the frame, thereby reducing errors inpattern formation.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a shape and a graph showing an interpretation ofdeformation of a frame, caused by the own weight of the frame.

FIG. 2 illustrates a shape and a graph showing an interpretation ofdeformation of an upper frame and deformation of a lower frame, causedby the own weight of the frames and tension of a tension mask.

FIG. 3 is a view illustrating an apparatus for manufacturing a tensionmask-frame assembly according to an embodiment of the present invention.

FIG. 4 is a schematic view illustrating a concept of pre-deforming aframe in consideration of deformation caused by tension of a tensionmask and the load of the frame.

FIG. 5 is a cross-sectional view illustrating an apparatus forpre-deforming a frame in consideration of deformation caused by tensionof a tension mask and the load of the frame.

FIG. 6 is a flowchart of a method for manufacturing a tension mask-frameassembly according to the present invention.

MODES OF THE INVENTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the accompanying drawings. It is however to beunderstood that the present invention is not intended to be limited tothe specific embodiments and the present invention includes variousmodifications, equivalents, and substitutions of embodiments of thepresent invention. In connection with descriptions of the drawings,similar components may be designated by the same reference numeral.

In the disclosure disclosed herein, the expressions “have,” “may have,”“include” and “comprise,” or “may include” and “may comprise” usedherein indicate the presence of corresponding features (for example,elements such as numeric values, functions, operations, or components)and do not preclude the presence of additional features.

In the disclosure disclosed herein, the expressions “A or B,” “at leastone of A and/or B,” or “one or more of A and/or B,” and the like usedherein may include any and all possible combinations of the associatedlisted items. For example, the term “A or B,” “at least one of A and B,”or “at least one of A or B” may refer to all of the case (1) where atleast one A is included, the case (2) where at least one B is included,and the case (3) where both of at least one A and at least one B areincluded.

The terms, such as “first,” “second,” and the like used herein, mayrefer to various elements of various embodiments of the presentinvention, but do not limit the elements. For example, such terms do notlimit the order and/or priority of the elements. Furthermore, such termsmay be used to distinguish one element from another element. Forexample, without departing from the scope of the present invention, afirst element may be referred to as a second element, and similarly, asecond element may be referred to as a first element.

It will be understood that when an element (for example, a firstelement) is referred to as being “coupled with/to” or “connected to”another element (for example, a second element), it can be directlycoupled with/to or connected to another element or coupled with/to orconnected to another element via an intervening element (for example, athird element). In contrast, when an element (for example, a firstelement) is referred to as being “directly coupled with/to” or “directlyconnected to” another element (for example, a second element), it shouldbe understood that there is no intervening element (for example, a thirdelement).

According to the situation, the expression “configured to (or set to)”used herein may be used as, for example, the expression “suitable for,”“having the capacity to,” “designed to,” “adapted to,” “made to,” or“capable of”. The term “configured to (or set to)” may not necessarilymean only “specifically designed to” in hardware. Instead, theexpression “a device configured to” may mean that the device is “capableof” operating together with another device or other components.

Terms used in the present invention are used to describe specifiedembodiments of the present invention and are not intended to limit thescope of other embodiments. The terms of a singular form may includeplural forms unless otherwise specified. Unless otherwise definedherein, all the terms used herein, which include technical or scientificterms, may have the same meaning that is generally understood by aperson skilled in the art. It will be further understood that terms,which are defined in a dictionary and commonly used, should also beinterpreted as is customary in the relevant related art and not in anidealized or overly formal way, unless expressly so defined herein invarious embodiments of the present invention. In some cases, even whenthe terms are terms which are defined in the specification, they may notbe interpreted to exclude the embodiments of the present invention.

When a tension mask is attached to a frame, the tension mask is tightlypulled in a lengthwise direction thereof. When the tension mask iscoupled to a support frame 12 in a state in which the tension mask isnot tightly pulled, a rough wave is generated in the tension mask. Therough wave reduces adhesion between the tension mask and a substrate ina subsequent deposition process, which functions as a factor whichhinders accurate deposition. Therefore, when the tension mask isattached to the support frame 12, both ends of the tension mask arewelded to the support frame 12 after the tension mask is tightly pulledin the lengthwise direction thereof. In order to weld the tension maskto the support frame 12 so as to have the same pattern as a pattern of athin film or the like to be formed on the substrate, the tension mask ispulled and is welded to the support frame 12 such that the pattern ofthe thin film and the pattern of the split tension mask match eachother. In this case, the tensioned tension mask pulls the support frame12 inward to deform the support frame 12. As a result, the pattern ofthe thin film and the pattern of the split mask do not match each other.In order to match the patterns, only when the support frame 12 ispre-deformed by applying a force by which the tension mask pulls thesupport frame 12 inward, the support frame 12 is not deformed after thewelding. The force pre-applied to pre-deform the support frame 12 isreferred to as a “counter force”.

For example, a tension mask-frame assembly 10 with a large size of 6 GHis used in an erected state in a vertical vacuum deposition method. Inthis case, the support frame 12 to which the tension mask is attached isdeformed by load thereof. Therefore, during vertical vacuum deposition,an appropriate force is pre-applied to pre-deform the support frame 12in consideration of load deformation of the support frame 12 accordingto the load. In this case, the force applied to minimize the loaddeformation is referred to as a “reverse counter force”.

FIG. 1 illustrates a shape and a graph showing own weight deformation ofa frame 10 with the size of 6 GH. As shown, when the frame 10 iserected, a middle portion of each of upper and lower support frames ismost deformed by load (gravity) thereof, and deformation is graduallydecreased toward both sides of each of the upper and lower supportframes. In this case, it can be seen that the upper and lower supportframes are deformed in a similar manner.

FIG. 2 illustrates a shape and a graph showing deformation of the framewith the size of 6 GH during each of horizontal deposition and verticaldeposition. As shown, it can be seen that tension and the load of thetension mask act in the same direction and thus deformation of the uppersupport frame during the vertical deposition is greater than that duringthe horizontal deposition. It can be seen that the tension and load ofthe tension mask act in opposite directions and thus deformation of thelower support frame during the vertical deposition is less than thatduring the horizontal deposition.

FIG. 3 illustrates an apparatus 100 for manufacturing a tensionmask-frame assembly according to an embodiment of the present invention.As shown, the apparatus 100 for manufacturing a tension mask-frameassembly includes a frame loading unit 110 configured to load a tensionmask-frame assembly 10, pressing units 120-1, 120-2, and 120-3configured to press a support frame between both ends thereof in a platesurface direction of the support frame, and a control unit 130configured to control the pressing units 120-1, 120-2, and 120-3.

The frame loading unit 110 functions to stably support a frame 10 so asto weld a tension mask. Although not shown in FIG. 3, the frame loadingunit 110 may further include a clamp (not shown) configured to clamp atension mask disposed on a pair of support frames 12 on the supportedframe 10, a pulling portion (not shown) configured to pull the clampedtension mask, and a welding portion (not shown) configured to weld bothends of the tension mask while moving along the support frame 12.

As shown in FIG. 4, the tension mask-frame assembly includes the frame10 with a rectangular frame shape which includes the pair of supportframes 12 to which opposite edges of the tension mask with a rectangularsheet shape are fixed, and a pair of connection frames 14 configured toconnect both ends of the support frames 12 to each other. The tensionmask-frame assembly may be applied to a tension mask which is split into12 pieces and fixed.

However, the tension mask-frame assembly may be applied to a tensionmask which is split into pieces of which the number is greater than orless than 12.

The pressing units 120-1, 120-2, and 120-3 press the support frames 12of the frame 10 outward and inward in a state of being supported by theframe loading unit 110. As shown in the enlarged view in FIG. 4, thepressing units 120-1, 120-2, and 120-3 each include an elastic pressingmember 122 and a driving body 124. A front end of the elastic pressingmember 122 may be moved forward and backward with respect to the supportframe 12.

The driving body 124 includes a driver (not shown) such as a motorconfigured to move the elastic pressing member 122 forward and backward,and a load cell (not shown). The load cell measures a force applied tothe support frame 12 through the elastic pressing member 122, and stopswhen the measured force reaches a value input in the control unit 130.The pressing units 120-1, 120-2, and 120-3 include first and secondinward pressing members 120-1 and 120-2 configured to press the pair ofsupport frames 12 inward in a plate surface direction from outside theframe, and outward pressing members 120-3 configured to press thesupport frame 12 outward in the plate surface direction from the insideto the outside of the frame. In FIGS. 3 and 4, 12 first inward pressingmembers 120-1, 12 second inward pressing members 120-2, and 7 outwardpressing members 120-3 are provided, but the present invention is notlimited thereto. The numbers of the first and second pressing members120-1 and 120-2 and the outward pressing members 120-3 may beappropriately adjusted and provided.

In consideration of deformation caused by tension of the tension mask 10and deformation caused by the load of the support frame 12, the firstinward pressing member 120-1 presses and pre-deforms an upper supportframe 12, i.e., a support frame 12 disposed at an upper side when thetension mask 10 is used in an vertically erected state. In this case, itis advantageous for only the first inward pressing member to adjust thetension and load acting on the support frame disposed at the upper sidein the same direction. Of course, it is also possible to install andapply a separate inward pressing member.

FIG. 5 is a schematic view illustrating a state in which a lower supportframe is pressed by the second inward pressing member 120-2 and theoutward pressing member 120-3.

By applying a force in consideration of deformation caused by tension ofthe tension mask 10, the second inward pressing member 120-2 presses andpre-deforms a lower support frame 12, i.e., a support frame 12 disposedat a lower side when the tension mask 10 is used in a vertically erectedstate.

The outward pressing member 120-3 is disposed in a slot 16 formed in alengthwise direction of the lower support frame 12, i.e., the supportframe 12 disposed at a lower side when the tension mask 10 is used in avertically erected state, and thus presses the support frame 12 outwardin the plate surface direction. In this case, the driving body 124 ofthe outward pressing member 120-3 presses the support frame only throughforward and backward movements of the elastic pressing member 122 in astate of being fixed to the frame loading unit 110.

In addition, the outward pressing member 120-3, which presses thesupport frame 12 disposed at the lower side, may be omitted, and thesupport frame 12 may be adjusted using only the second inward pressingmember 120-2. That is, the support frame 12 may be adjusted so as tooffset gravity acting in an opposite direction to tension of the tensionmask.

In this case, since the number of variables, which should be taken intoconsideration when a plurality of pressing members are adjusted forpre-deforming, is increased, there are a few disadvantages in terms ofoperation.

The control unit 130 is implemented as a computer including a processorfor controlling the motor and the load cell included in each of thepressing units 120-1, 120-2, and 120-3. The processor may be implementedby hardware such as a control board, software, or a combination ofhardware and software, wherein the control board includes a centralprocessing unit (CPU), a micro processing unit (MPU), applicationspecific integrated circuits (ASICs), digital signal processors (DSPs),digital signal processing devices (DSPDs), programmable logic devices(PLDs), field programmable gate arrays (FPGAs), micro-controllers,microprocessors, etc.

The control unit 130 may obtain and store a bending deformation value ofthe support frame caused by tension of the tension mask 10 and a bendingdeformation value of the support frame caused by load in advance througha simulation. The control unit 130 controls the pressing units 120-1,120-2, and 120-3 to pre-deform the support frame in accordance with atleast a portion of the stored bending deformation value of the supportframe caused by the tension and the stored bending deformation value ofthe support frame caused by the load.

FIG. 6 is a flowchart of a method for manufacturing a tension mask-frameassembly method according to the present invention.

In operation S11, the frame 10 is loaded on the frame loading unit 110.In this case, the frame 10 is in a state in which the tension mask 1 isnot welded thereto, and is stably supported by the frame loading unit110. The frame loading unit 110 supports the frame 10 such that theframe is not moved by the pair of connection frames 14. In this case,the first inward pressing member 120-1 is disposed in contact with anouter surface of the upper support frame 12 of the frame 10. The secondinward pressing member 120-2 is disposed in contact with an outersurface of the lower support frame 12. The outward pressing member 120-3is disposed in contact with an inner surface of the lower support frame12. The pressing members 120-1, 120-2, and 120-3 are in contact with theouter surface or the inner surface of the support frame 12 and do notpress the support frame 12.

In operation S12, the control unit 130 controls each of the pressingmembers 120-1, 120-2, and 120-3 to apply a force to the upper supportframe and the lower support frame, wherein the force corresponds totension of the tension mask and the load of the support frame. As aresult, the support frame 12 of the frame 10 is pre-deformed by a forcecorresponding to the tension of the tension mask and the load of thesupport frame in a state in which the tension mask is not attachedthereto. In this case, a pattern of the tension mask is set to beapplied during vertical deposition.

In operation S13, the tension mask to be welded is clamped on the frame10 in a state in which the support frame 12 is pre-deformed. In thiscase, both ends of the tension mask are fixed by a clamp.

In operation S14, the clamped tension mask is tensioned by applyingtension corresponding to the tension applied in operation S12.

In operation S15, both ends of the tension mask to which tension isapplied are fixed to the pair of deformed support frames 12, forexample, through wielding. In this case, when a pressurizing state ofeach of the pressing members 120-1, 120-2, and 120-3 is released, thedeformed support frames 12 are balanced by the tension mask to whichtension is applied. However, in a horizontal state, the support frame 12is restored by a load deformation amount in additional consideration ofload. As a result, such restoration causes the pattern of the tensionmask to deviate from a state set to be applied during verticaldeposition. When the tension mask-frame assembly is erected for verticaldeposition, the support frame 12 is again in the deformed state set inoperation S12 by the load of the support frame 12. As a result, thepattern of the tension mask is also in a state set to be applied forvertical deposition. As described above, when the tension mask-frameassembly is manufactured, the support frame may be pre-deformed inconsideration of pre-deformation, and then, the tension mask may bewelded, thereby preventing the pattern of the tension mask from beingchanged due to the tension of the tension mask or the load of thesupport frame.

While the present invention has been described with reference to thelimited exemplary embodiments and the drawings, the present invention isnot limited to the exemplary embodiments, and it will be understood bythose or ordinary skill in the art that various modifications andalterations may be made therein.

Therefore, it should be noted that the scope of the present invention isnot limited to the exemplary embodiments described above and isdetermined by the claims and equivalents thereof.

1. An apparatus for manufacturing a tension mask-frame assembly in whicha tension mask is mounted on a frame which has a rectangular frame shapeand includes a pair of support frames, to which opposite edges of thetension mask with a rectangular sheet shape are fixed, and a pair ofconnection frames configured to connect both ends of the support framesto each other, the apparatus comprising: a frame loading unit configuredto load a tension mask-frame assembly; a pressing unit configured topress the support frame between both ends thereof in a plate surfacedirection of the support frame; and a control unit configured to controlthe pressing unit to pre-deform the support frame in accordance with atleast a portion of a bending deformation amount of the support frame,caused by own weight of the support frame and tension of the tensionmask.
 2. The apparatus of claim 1, wherein the pressing unit includes aplurality of inward pressing members which are spaced apart from eachother in a lengthwise direction of the pair of support frames and pressthe pair of support frames toward the inside of the frame.
 3. Theapparatus of claim 2, wherein the pressing unit includes a plurality ofoutward pressing members which are spaced apart from each other in thelengthwise direction of the support frame and press the support frametoward the outside of the frame.
 4. The apparatus of claim 2, whereinthe control unit controls the pressing member based on a predicted ownweight deformation amount of each of the pair of the support frames anda tension deformation amount of the tension mask.
 5. A method ofmanufacturing a tension mask-frame assembly in which a tension mask ismounted on a frame which has rectangular frame shape and includes a pairof support frames, to which opposite edges of the tension mask with arectangular sheet shape are fixed, and a pair of connection framesconfigured to connect both ends of the support frames to each other, themethod comprising: loading the frame on a frame loading unit;pre-deforming the support frame in accordance with at least a portion ofa bending deformation amount of the support frame, caused by own weightof the support frame and tension of the tension mask; clamping thetension mask on the pre-deformed frame; tensioning the tension mask; andfixing the tensioned tension mask to the pre-deformed frame.
 6. Theapparatus of claim 3, wherein the control unit controls the pressingmember based on a predicted own weight deformation amount of each of thepair of the support frames and a tension deformation amount of thetension mask.